Simplify the expression. $(7k^{4}+7k^{3}+4k)(-5k)$
First use the distributive property. $ 7 k^4 (-5 k) + 7 k^3 (-5 k) + 4 k (-5 k) $ Simplify. $-35k^{5}-35k^{4}-20k^{2}$